The present invention relates to a cold storage structure including a storage space for storing articles, the storage space being adapted to be cooled with a frozen material surrounding it.
It is known that cylindrical heat pipes are vertically erected on the ground to surround a cold storage chamber, formed in the ground, with underground portions thereof for producing frozen soil portions in the ground around the storage chamber to cool the latter. The heat pipe is a device in which heat is transferred according to phase change of an operating medium, contained in it, between the gaseous phase and the liquid phase. The frozen soil is produced with the cold atmosphere in the winter.
This cold storage structure is disadvantageous in that a condensed working medium which is condensed at the upper portion of the sealed cylindrical casing of each heat pipe rapidly drops to the bottom of the casing, so that evaporation of the condensed medium occurs mainly at the bottom portion thereof. Thus, endothermic action of heat pipes is limited to their bottom portions, and hence it is hard to produce a frozen soil layer having a large vertical thickness, which is capable of uniformly cooling a cold storage chamber having a relatively large height.
Accordingly, it is an object of the present invention to provide a cold storage structure which is capable of producing a frozen material having a relatively large thickness around the storage space for uniformly cooling the latter.